Chevron axial seal assemblies are used to provide a fluid barrier between oppositely facing generally cylindrical concentric walls, particularly in subterranean applications under conditions of high pressure and/or high temperature. Known chevron axial seal assemblies are shown, for example, in U.S. Pat. Nos. 4,234,197; 4,406,469; 4,433,847; 4,811,959; 5,131,666; 5,156,220; 5,297,805; 5,309,993; 6,406,028; 7,401.788; 7,445,047; and in U.S. Patent Publications 2009/0277642 and 2003/0222410. A radially inner part of the chevron seal assembly engages and seals against the radially inner cylindrical wall, and a radially outer part of the chevron seal assembly engages and seals against the radially outer cylindrical wall. Chevron seals of this general type may be used in static and/or dynamic applications.
Chevron seal assemblies may include seal subassemblies that have multiple components that provide various functions. Spacer rings separate adjacent unidirectional seal subassemblies, each of which may seal in a direction opposite the other, or separate other components. Scraper rings wipe or scrape debris from a surface that is to be sealed. Sealing rings provide the described sealing engagement between the concentric walls. Anti-extrusion rings, also called back up rings, prevent less rigid rings from extruding between the concentric cylindrical walls that are being sealed.